Sex identification of human blood, bloodstains, saliva, hair roots and bone marrow was conducted by DNA analysis. The effects of various contaminants in samples on sex identification were studied, using 32-week-old contaminated bloodstains. The effect of heat or decomposition on sex identification was examined by using the blood obtained from autopsy-cases. A 2.12 kb band with male DNA, digested with Hae Ⅲ and electrophoresed, was observed by Southern hybridization using a human Y chromosome-specific probe, while a faint 2.00 kb band with female DNA was also sometimes detected. The male 2.12 kb band was detected even in 5-year-old bloodstains. The 2.12 kb band was also detected frequently in contaminated bloodstains as old as 32 weeks. The band was observed by Southern hybridization analysis in decomposed blood as old as 7 days, while it could not be detected in heated and decomposed blood after 3 days.
deoxyribonucleic acid (DNA)